If the the hypothesis on AP possessors memorizing groups or patterns of notes is true (i think it is), it might be good to have a game where u identify basic structures like major and minor chords absolutely.

Yeah... that's where my thinking has also led me. I haven't been sure whether it'd be an extension of Interval Loader or a resurrection of Chordfall or something else altogether, but it seems pretty obvious that there should be a game where the point would be to identify the structure and/or root of a chord-- something more musically deliberate than Chordhopper.

This work is really still in its infancy. Although I feel as though four-going-on-five years is quite a long time to have pursued this single question, the paper I'm looking at right now is an author's 1994 followup to the same study he conducted in 1974. I've seen at least five or six tasks which must be incorporated into the game (e.g. dictation) but I need to figure out the best way to do't and then actually make em happen.